+ Add gdb in the development Docker image to help debugging (#323)

sysdig-CLA-1.0-signed-off-by: Jean-Philippe Lachance <jplachance@coveo.com>

docker/dev/Dockerfile

@@ -24,7 +24,8 @@ RUN echo "deb http://httpredir.debian.org/debian jessie main" > /etc/apt/sources
 	ca-certificates \
 	gcc \
 	gcc-5 \
-	gcc-4.9 && rm -rf /var/lib/apt/lists/*
+	gcc-4.9 \
+	gdb && rm -rf /var/lib/apt/lists/*
 
 # Since our base Debian image ships with GCC 5.0 which breaks older kernels, revert the
 # default to gcc-4.9. Also, since some customers use some very old distributions whose kernel